Harmonic generator



' Filed -July 2s., 1946 4 sheets-sheet 1 D. 27,1949 G, GUANE'LLA 2,492,218

HARMONIC GENERATOR 6' Eff V2 TF2 5mm L 0 W O sc/LL n 102 Pa Mom/Lafon Pass Fu. TEA FILTER AEnc vnNcE CONrkoL swcs ATTORNEY Dec. 27, 1949 e. GUANELLA HARMONIC GENERATOR 4 Sheets-Sheet 2 Filed July 2s, 1946 G EL R fw wmE m nvm n w in ma n R 0 2 P fr B m 0 fr ps2 E BPH R P m n n w m A Nn., m. m w im M .n M Pl l rm| M 5 f P 0 5 m asm NST m .WHL n fr rh 60N Trol. DEV/aE PHN S E dsc/Maron' Mom/MTM INVENTOR Gus ra v GL/QNELLA ATTORNEY i; 27, '1949 G. GUANELLA HRMoNIc GENERATOR 4 Sheets-Sheet 5 :Filed July 25, 194e INVENTOR Gus-rnv Guxme-Ln lv( ia. ATTORNEY G G UAN ELLA HARMONIC GENERATOR 4 Sheets-Sheet- 4 Filed July as, 194s w. am

This is the (11H-mth harmonic of the fundamental frequency fi. Since the carrier oscillation disappears, the special advantage of this method is that the carrier frequency does not need to be highly constant or stable. With a carrier frequency of a few megacycles and a fundamental frequency f1 of 1 kc. the deviation or limits of frequency variation may amount to over 100 kc. Side band frequencies with n=m=100 then occur. There is thus a, multiplication of the fundamental frequency f1 up to a factor n-l-m=200.

Fig. 3 shows a, further modified arrangement according to the invention. 'Ihe difference between this arrangement and that shown in Fig. 2 is the fact that the band-pass lters are for different frequency ranges. Band-pass filter BP; allows the carrier frequency and all upperside band frequencies up to the nth component to pass, that is fu-i-Zmfi. Band-pass filter BP2 only allows the frequency fo-mfi to pass. After passing the modulator M and the low-pass filter TP, a spectrum of successive oscillations 2(m+n)f1 is obtained.

Fig. 4 shows an arrangement which prevents the amplitudes of individual components in the spectrum from disappearing. It is based on the fundamental arrangement shown in Fig. 1. At the output end of the low-pass filter TP, where the fundamental frequency f1 and the spectrum of its harmonics are present, provision is made to feed back or return a portion of the output over a band filter BPa and a frequency multiplier V to the reactance control element R. If a harmonic, for instance the pth harmonic, is very weak or not even present, the fundamental frequency ,f1 is multiplied p-times in the multiplier. The current or voltage of frequency pfi which is thus obtained, is then applied to the reactance control R of the generator G together with the current of fundamental frequency f1. The side bands fuipfi which were missing from theoriginal spectrum are now present in the spectrum of the frequency-modulated oscillation of generator G. Further harmonics are also formed which a may cause a desired amplification of further Weak harmonics. The additional multiplier V may be omitted, this depending upon the amplitude distribution of the frequency spectrum.

Two practical applications of the method according to the invention are now described. Fig. 5 shows an arrangement for dividing a given frequency. The input energy of frequency which is to be reduced to the frequency f1, is applied to the amplitude modulator M1. In the latter it is superposed upon energy of auxiliary frequency (m-l-n)f1, so that at the output end the frequency f1 appears.

The auxiliary frequency (m-}-n)f1 is derived from the output by using the device according to the invention. The procedure is as follows: The output frequency f1 is passed to the reactance control element R and frequency modulates generator G having an average or center frequency fo. The generator voltage is passed to the bandpass filters BP; and BP2. Filter BP; allows frequency fo+nf1 and lter BP2 allows the frequency fo-mf1 to pass and suppresses all the other frequencies, including also the carrier frequency fo. Both frequencies reach the amplitude modulator M. The resulting difference frequency (m-I-n) f1 is passed over the band-pass lter BP to the modulator Mi already referred to. The

entire system is a feed-back system capable of Y oscillating; stable conditions occur, however, if the frequency is divided in the ratio 1/m+n+1.

The device according to the invention may also be used for the frequency multiplication of phasemodulated signals. Such an arrangement is shown in Fig. 6. V indicates the frequency multiplier which has already been described, with the difference that the frequency fi of the input signal applied to the reactance control R is already phase-modulated. The average or center frequency is fg and is produced by generator G1. By means of phase modulator PM frequency fg is phase-modulated by the signal S which is to be transmitted; f1 is then the phase-modulated frequency applied to the input end of the frequency multiplying device. The multiplication produces an average frequency (m4-n) fg multiplied by the factor (1n-HL), while at the same time the frequency deviation or variation limits are multiplied by the same factor.

After having explained the principle on which the device according to the invention operates, a few examples of more detailed diagrams of connections required for the individual basic arrangements are given. Figs. 7, 8, 9 show detailed diagrams corresponding, respectively, to the basic arrangements illustrated in Figs. 1, 2 and 4. Corresponding diagrams for the arrangements of Figs. 3, 5 and 6 may be obtained by an analogous combination of the elements R, G, BP, M and TP. The reactance control element R shown is of the known type comprising a multi-grid electron tube. A condenser is connected between the anode and the control grid. The input voltage with a frequency f1 shifts the control grid voltage, whereby corresponding frequency alterations occur in the tube generator G in a manner well known to those skilled in the art. The subsequent band-pass lters BP, BPi as well as the lowpass filter TP are wave filters constructed in a known manner. Modulator M is of the type comprising two diodes which produce the de modulated voltage across a condenser-resistance load circuit. In Fig. 9, a frequency multiplier is shown. This contains a very powerful amplifier tube with non-linear characteristic and an anode circuit tuned to a harmonic of the frequency fr.

I claim:

1. A method of producing harmonics from a fundamental frequency comprising the steps of subjecting an auxiliary carrier frequency to a frequency modulation process in accordance with said fundamental frequency and mutually intermodulating at least two side band frequencies obtained from said modulation process.

2. A method of producing harmonics from a fundamental frequency comprising the steps of frequency modulating an auxiliary carrier frequency in accordance with said fundamental frequency to produce a plurality of adjacent side band frequencies differing from each other by said fundamental frequency, and mutually intermodulating at least two of said side band frequencies to produce a harmonic of said fundamental frequency.

3. A method of producing harmonics from a fundamental frequency comprising the steps of frequency modulating an auxiliary carrier frequency in accordance with the fundamental frequency, theefrequen'cx'rY deviation froirrsaldoarrie frequency being arelativelylargemultiple ofsaid fundamental7 frequency, segregating aA predeer terminedb'and of side band frequenciesrfrcm tlie modulation-produca; andmutually inter-modulat' ing said: side bandf'- frequencies.-`

4: A method of; producing harmonics;v from afundamentalt frequency comprising; thest'epsiof frequency-V modulating an`-v auxiliary carrierY frei-f quencyA in accorda-nce with* saidi findamental frequency; the* frequencyf deviation'` from said--Y carrier frequency being' a"relativelylvlargemultiple of-'saidffundamenta'l frequency; segregating aipre': determined band o'f sidebandi frequen'cie'se from? the modulations produce, mutually; iritermodulateYy ing'saidside ban'dfre'quencies to`=produce a" spec#v trum` ofZ harmonics o'f said lfundar'nx-entail" fre quencies, :and selectingva desired harmonic-1. from? said spe'ctrun'i:v

5. A systemfor producingI harmonics from a fundamental frequency'comprising' an auxiliary oscillatorl having;a `frequency` substantiallyfhigher than the highest harmonic offsaidfundamentalfrequency to. be` produced, .frequency modulating means for`modulati`1figsaidoscillator'in accord- 2 ance with said fundamentalfrequency to producer a. plurality? of, different ,o order; modulationl side band frequencies. progressively-spaced from each otlienby intervals. equal.tv sadffundamental fre"- quency, and meansfor, deriving vand mutually in- A termodulating at least"tiwo`ofthe"side band frequencies-of said oscillatortoiproduce a differenceEv frequencyifcorrespondirigito:thefzdesired Harmonic of said fundamental frequency.

Gf. A system for producing harmonics from a fundamental frequency comprising an auxiliary oscillator having a frequency substantially higher than the highest harmonic frequency to be produced, frequency modulating means for modulating said oscillator in accordance with said fundamental frequency to produce a plurality of different order side band frequencies progressively spaced from each other by intervals equal to said fundamental frequency, means for deriving a plurality of side band frequencies from said oscil- 4 lator, further means for mutually intermodulating the derived side band frequencies, and means for selecting the desired harmonic from the resultant modulation product.

'7. A system for producing harmonics from a a fundamental frequency comprising an auxiliary oscillator,` means for frequency modulating said oscillator in accordance with said fundamental frequency, the frequency deviation from the normal oscillating frequency being relatively large compared with said fundamental frequency to produce a plurality of different order modulation side band frequencies progressively spaced from each other by said fundamental frequency, bandpass filter means connected to said oscillator, and means connected to the output of said filter means for mutually intermodulating the side band frequencies selected by said filter means.

8. A system for producing harmonics from a fundamental frequency comprising an auxiliary oscillator, frequency modulating means for modulating said oscillator in accordance with said fundamental frequency, the frequency deviation from the normal oscillating frequency being relatively large compared With said fundamental frequency to produce a plurality of different order modulation side band frequencies progressively spaced from each other by said fundamental frequency, band-pass filter means connected to said oscillator for selecting therefrom a plurality of A quencies" of" frequency .Y spectively; whereinm and n arewhole numbers;

and" an airipiitude` modulator c'orinectecl to' bctrr said narici-:pass mters-'formutuaiiy interrnoaiatf-f ing" the' side; band f'e'quen'cies selectedE by said?" ltersandto produce fi'ainionicombinatioiifreir p Y mf+mf r 10. A system for pro'ducir'ig:I harmjo'riicsfiorfi aiy fundamental' frequency ofi value* f" coiipr'isii'gfI an auxiliary` oscillator producir'fgvr a'` normal" frei quency. orvaiuef-ft; meansficrfffequency modulatiing vvsaid oscillator 'inaccordanceyvith'said fundamental frequency; the fiicpieii''cy4y deviation* from" said normal kfrequency beingi relativelylargeconf parediwith said'fundamentalfr'equ t'opro duce a'p-iuraiity cfidiferentiorderimcuiatiorisidiband frequencies progressively spaced from each other by said fundamental frequency, a pair of band-pass filters connected to said oscillator and having frequency passing ranges fo-l-mf and ffl-nf, respectively, wherein m and n are whole numbers, an amplitude modulator connected to both said band-pass filters for mutually intermodulating the side band frequencies selected by said filters and to produce harmonic combination frequencies of frequency (m-l-n) f, and a low-pass filter connected to the output of said modulator having a limit frequency equal to (m4-n) f.

11. A system for producing harmonics from a. fundamental frequency comprising an auxiliary oscillator having a frequency substantially higher than the highest harmonic of said fundamental frequency tobe produced, frequency modulating means for modulating said oscillator in accordance with said fundamental frequency to produce a plurality of different order modulation side band frequencies progressively spaced from each other by intervals equal to said fundamental frequency, and a band-pass filter having a passing range to encompass a pair of said side band frequencies spaced by a frequency interval equal to a desired harmonic of said fundamental, and means for mutually intermodulating the side band frequencies selected by said filter and for selecting the difference frequency from the resultant modulation product.

12. A system for producing harmonics from a fundamental frequency comprising an auxiliary oscillator having a frequency substantially higher than the highest harmonic of said fundamental frequency to be produced, frequency modulating means for modulating said oscillator in accordance with said fundamental frequency to produce a plurality of different order modulation side band frequencies progressively spaced from each other by intervals equal to said fundamental frequency, and a band-pass lter connected to said ing said oscillator in accordance with said fundamental frequency, the frequency deviation from said normal frequency being relatively large com-l pared with said fundamental frequency to produce a plurality of different order modulation side band frequencies progressively spaced from each other by a frequency range equal to said fundamental frequency, a pair of band-pass filters connected to said oscillator having frequency passing ranges fo-f-Enf and fo-mf, respectively, wherein m and n are Whole numbers, and amplitude modulating means connected to both said filters for mutually inter-modulating the side band frequencies selected by said filters and to produce harmonic components of frequency 20ml-mf.

14. A system for producing harmonics from a fundamental frequency of value ,f comprising an auxiliary oscillator producing a normal frequency of value fo substantially higher than said fundamental frequency, means for frequency modulating said oscillator in accordance with said funda# mental frequency, the frequency deviation from said normal frequency being relatively large compared with said fundamental frequency to produce a plurality of different order modulation side band frequencies progressively spaced from each other by a frequency range equal to said fundamental frequency, a pair of band-pass filters connected to said oscillator and having frequency passing ranges fo-l-Enf and fo-mf, respectively, wherein m and n are whole numbers, amplitude modulating means connected to both said filters for mutually intermodulating the side band frequencies selected by said lters and to produce harmonic components of frequency 20u-HL) f, and low pass lter means connected to the output of said modulating means having a limit frequency equal to (m-l-mf.

GUSTAV GUANELLA.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,719,052 Green July 2, 1929 1,901,043 Roosenstein Mar. 14, 1933 2,337,533 Barber 1 Dec. 28, 1943 FOREIGN PATENTS Number Country Date 486,448 Great Britain June 2, 1938 

